A little more than a week ago, Alexandria’s GenOn — formerly Mirant — power plant permanently shut down. How did this happen?

It happened because the city and its residents were committed. They persisted for more than 11 years to ensure it closed. And, yes, recent market conditions also contributed to the plant’s demise.

Yet, the story is more complex. Early on, Poul Hertel and I brought public health issues associated with the facility’s polluting emissions to the city’s attention, including producing a report citing health effect studies from those emissions and likely dispersion problems at the plant. We first discussed our concerns with City Councilor Paul Smedberg. He consistently spearheaded this issue as more scientific-based information was collected, especially the preliminary study demonstrating that the plant was exceeding its permitted sulfur dioxide limit.

Mayor Bill Euille evaluated the developing scientific data, realized the public health threat to residents and directed then City Attorney Ignacio Pessoa to pursue the issue. City staff immediately pushed ahead, determining that a much larger scope of pollutants was affecting Alexandrians’ health.

Meanwhile, concerned residents held a meeting to discuss the plant’s emission effects on public health and, in particular, those living near the plant. Throughout the 11 year journey, residents wrote letters and spoke at state air board meetings in Richmond and Alexandria, creating a critical mass of support behind city staff’s ever developing science and engineering findings.

With the mayor’s creation of the Mirant community monitoring group, chaired by City Councilors Del Pepper and Smedberg, the resident-city alliance stayed alive and investigated ongoing issues with staff, Mirant officials and Virginia Department of Environmental Quality representatives.

There were difficulties and disappointments throughout the years. The city, attempting to rezone the property, lost in court. The federal Energy Department, because of electric reliability concerns, ordered the plant kept open, even as it exceeded national environmental standards. We struggled, but we persisted.

And there were advances and successes. VDEQ mandated the plant to close, based on a scientific study showing the facility’s multiple exceedances of national air quality standards. The city and Mirant agreed the company would invest $34 million in pollution controls at the facility.

So, how did it happen that the GenOn power plant powered down last week? Who did it?